Nervous System Lecture Notes PDF

Nervous System Dr.Basmal Abdulkareem Nervous System The Nervous System is divided into Two Main Divisions: Central Nervous System (CNS) and the Peripheral Nervous System (PNS) Functions of the Nervous System: 1. Gathers information f...

Nervous System Dr.Basmal Abdulkareem Nervous System The Nervous System is divided into Two Main Divisions: Central Nervous System (CNS) and the Peripheral Nervous System (PNS) Functions of the Nervous System: 1. Gathers information from both inside and outside the body - Sensory Function 2. Transmits information to the processing areas of the brain and spine 3. Processes the information in the brain and spine – Integration Function 4. Sends information to the muscles, glands, and organs so they can respond appropriately – Motor Function. Central Nervous System Brain o Cerebellem o Cerebrum o Brain stem – medulla, pons, midbrain o Diencephalon – thalamus & hypothalamus Spine o Spinal Cord  Nervous System Dr.Basmal Abdulkareem Meanings: Body membranes that cover the brain and spinal cord for protection and nourishing purposes. Consists of 3 layers: a) Dura mater ("tough mother"): outermost layer that attaches the brain to cranial bones, and the spinal cord to vertebrae. b) Arachnoid mater ("web like mother"): middle layer made up of thin membranes that lack blood vessels. c) Pia mater ("gentle mother") innermost layer made of thin membranes that contain capillaries for providing nourishment to the brain and spinal cord  Nervous System Dr.Basmal Abdulkareem Cerebrum: Is the largest portion of the brain encompasses about two-thirds of the brain mass. a) Cerebral Cortex (outer region): is made of gray matter which contains up 75% of all neurons in the nervous system, while Cerebral Medulla (inner region) is made of white matter. b) Consists of left and right hemispheres, created by the longitudinal fissure at the center of cerebrum. Lobes of the Cerebrum: Frontal – motor area involved in movement and in planning & coordinating behavior Parietal – sensory processing, attention, and language Temporal – auditory perception, speech, and complex visual perceptions Occipital – visual center – plays a role in processing visual information  Nervous System Dr.Basmal Abdulkareem Vasculature: The blood supply to the cerebrum can be simply classified into 3 distinct paired arterial branches: *Anterior Cerebral Arteries. *Middle Cerebral Arteries. *Posterior Cerebral Arteries.  Nervous System Dr.Basmal Abdulkareem Cerebellum: Coordinates and controls muscular movement and muscle tone. Maintains body posture, by working with the equilibrium receptors in the inner ear During embryonic development, the anterior portion of the neural tube forms three parts that give rise to the brain and associated structures: Forebrain (prosencephalon) Midbrain (mesencephalon) Hindbrain (rhombencephalon) The hindbrain subsequently divides into: the metencephalon (superior) and the myelencephalon (inferior). The cerebellum develops from the metencephalon division. Structural Development of The Brain Embryonic vesicle: Forebrain (Prosencephalon) a. Anterior portion (Telencephalon) produces Lateral Ventricles, cerebrum and basal ganglia. b. Posterior portion (Diencephalon) produces Third Ventricle, Thalamus, Hypothalamus, post. Pituitary gland, and pineal gland. Embryonic vesicle: Midbrain (Mesencephalon) produces cerebral aqueduct, and midbrain. Embryonic vesicle: Hindbrain (Rhombencephalon) a. Anterior portion (Metencephalon) produces fourth ventricle, cerebellum, and pons. b. Posterior portion (Myelencephalon) produces fourth ventricle, and medulla oblongata.  Nervous System Dr.Basmal Abdulkareem Functional Divisions:  Nervous System Dr.Basmal Abdulkareem Vasculature: The cerebellum receives its blood supply from three paired arteries: *Superior cerebellar artery (SCA). *Anterior inferior cerebellar artery (AICA). *Posterior inferior cerebellar artery (PICA). Brain Stem: Made of brain tissue at the base of cerebrum connecting the cerebrum to the spinal cord. Functions largely for autonomous activities. Subdivided into diencephalon, midbrain, pons and medulla oblongata. Spinal Cord: A long nerve cord that begins at the foramen magnum and ends at the first or second lumbar vertebra. Divided into 31 segments (named after the vertebral regions), each segment gives rise to a pair of spinal nerves (part of the PNS).